import { NextRequest, NextResponse } from 'next/server'
import { AIClient } from '@/lib/ai-assistant'
import { getUser } from '@/lib/auth'

export async function POST(request: NextRequest) {
  try {
    // 验证用户身份
    const user = await getUser(request)
    if (!user) {
      return NextResponse.json(
        { message: '请先登录' },
        { status: 401 }
      )
    }

    const body = await request.json()
    const { prompt, conversationId } = body

    if (!prompt || !prompt.trim()) {
      return NextResponse.json(
        { message: '请输入您的问题' },
        { status: 400 }
      )
    }

    let client = new AIClient()    // 创建流式响应
    const encoder = new TextEncoder()
    let newConversationId: string | null = null
    const stream = new ReadableStream({
      async start(controller) {
        try {
          for await (const segment of client.processQuery(prompt, user.id, conversationId)) {
            // 检查是否是新对话ID
            if (segment.startsWith('conversation_id:')) {
              newConversationId = segment.substring('conversation_id:'.length)
              controller.enqueue(encoder.encode(`data: ${JSON.stringify({ conversationId: newConversationId })}\n\n`))
              continue
            }
            controller.enqueue(encoder.encode(`data: ${JSON.stringify({ content: segment })}\n\n`))
          }
          controller.enqueue(encoder.encode('data: [DONE]\n\n'))
          controller.close()
        } catch (error) {
          console.error('AI 处理错误:', error)
          controller.enqueue(encoder.encode(`data: ${JSON.stringify({ 
            error: error instanceof Error ? error.message : '处理请求时发生错误' 
          })}\n\n`))
          controller.close()
        }
      }
    })

    return new Response(stream, {
      headers: {
        'Content-Type': 'text/event-stream',
        'Cache-Control': 'no-cache',
        'Connection': 'keep-alive',
      },
    })

  } catch (error) {
    console.error('AI 查询错误:', error)
    return NextResponse.json(
      { message: 'AI 服务暂时不可用，请稍后再试' },
      { status: 500 }
    )
  }
}

export async function GET() {
  return NextResponse.json({
    message: '欢迎使用 PC DIY 商店 AI 助手！',
    examples: [
      '推荐一些价格在 1000-2000 元的显卡',
      '查找华硕品牌的主板',
      '什么是最新的 CPU 配件',
      '显示所有配件类型'
    ]
  })
}